Cette thèse à pour objet l’étude des résonances du laplacien sur les variétés à pointes. Ce sont des variétés dont les bouts sont des pointes hyperboliques réelles. Ces objets ont été introduits par Selberg pour les surfaces à pointes de courbure constante dans les années 50. Leur définition a ensuite été étendue en courbure variable par Lax et Phillips. Les résonances sont les poles d’une famille méromorphe de fonctions propres généralisées du laplacien. Elles sont associées au spectre continu du laplacien. Pour analyser ce spectre continu, plusieurs directions de recherche sont explorées ici. D’une part, on obtient des résultats sur la localisation de ces résonances. En particulier, si la courbure est négative, on montre que pour un ensemble générique de métriques, les résonances se séparent en deux ensembles. Le premier est contenu dans une bande près du spectre continu. L’autre partie est composé de résonances qui s’éloignent du spectre. Ceci laisse une zone de taille log sans résonance.D’autre part, on étudie les mesures microlocales associées à certaines suites de paramètre spectraux. En particulier, on montre que pour des suites de paramètres spectraux qui s’approche du spectre, mais pas trop vite, la mesure microlocale associée est nécessairement la mesure de Liouville. Cette propriété est valable quand la courbure de la variété est négative. / In this thesis, we study the resonances of the Laplace operator on cusp manifolds. They are manifolds whose ends are real hyperbolic cusps. The resonances were introduced by Selberg in the 50's for the constant curvature cusp surfaces. Their definition was later extended to the case of variable curvature by Lax and Phillips. The resonances are the poles of a meromorphic family of generalized eigenfunctions of the Laplace operator. They are associated to the continuous spectrum of the Laplace operator. To analyze this continuous spectrum, different directions of research are investigated.On the one hand, we obtain results on the localization of resonances. In particular, if the curvature is negative, for a generic set of metrics, they split into two sets. The first one is included in a band near the spectrum. The other is composed of resonances that are far from the spectrum. This leaves a log zone without resonances. On the other hand, we study the microlocal measures associated to certain sequences of spectral parameters. In particular we show that for some sequences of parameters that converge to the spectrum, but not too fast, the associated microlocal measure has to be the Liouville measure. This property holds when the curvature is negative.

Die vorliegende Arbeit beschäftigt sich mit der Höhe (-log Determinante) kompakter nicht-singulärer heisenbergartiger Nilmannigfaltigkeiten. Heisenbergartige Nilmannigfaltigkeiten sind Verallgemeinerungen von Heisenbergmannigfaltigkeiten, d.h., kompakter Quotienten der Heisenberg-Gruppe, ausgestattet mit einer linksinvarianten Metrik. Zunächst werden explizite Formeln für die spektrale Zeta-Funktion und die Höhe bewiesen. Mithilfe dieser Formeln werden im Weiteren mehrere Resultate zur Existenz unterer Schranken/Minima der Höhe auf verschiedenen Moduli bewiesen. Zum Beispiel ist die Höhe stets von unten beschränkt, wenn man nur Metriken vom Heisenberg-Typ und mit Volumen 1 auf einer gegebenen Nilmannigfaltigkeit betrachtet. Im Gegensatz dazu hängt die Existenz unterer Schranken für die Höhe auf dem Modulraum der heisenbergartigen Metriken mit Volumen 1 von der Dimension Modulo 4 der zugrundeliegenden Mannigfaltigkeit ab. Im letzten Abschnitt werden konkrete Minima der Höhe behandelt. Wir zeigen, dass gewisse 3-, 5-, 9- und 25-dimensionale Nilmannigfaltigkeiten vom Heisenberg-Typ lokale Minima sind. Diese stehen in Zusammenhang mit den Minima der Höhe flacher Tori in der jeweiligen Dimension minus 1. Zum Abschluss werden diejenigen linksinvarianten Metriken charakterisiert, an denen die Höhe ein globales Minimum auf einer gegebenen dreidimensionalen Nilmannigfaltigkeit annimmt, indem sie zur Höhe flacher 2-dimensionaler Tori in Bezug gesetzt werden. / This thesis deals with the height (-log determinant) of compact nonsingular Heisenberg-like nilmanifolds. Heisenberg-like nilmanifolds are generalisations of Heisenberg manifolds, i.e., compact quotients of the Heisenberg group endowed with a left invariant metric. First, an explicit formula for the spectral zeta-function and the height is proved. By means of these formulas, several results concerning the existence of lower bounds/minima for the height on different moduli are proved. For example, while the height is always bounded from below when one considers only volume normalised Heisenberg-type metrics on a fixed nilmanifold, the existence of lower bounds for the height on the moduli space of volume normalised Heisenberg-like metrics depends on the dimension modulo 4 of the underlying nilmanifold. In the last part, we consider concrete minima of the height on Heisenberg manifolds. We show that certain 3-, 5-, 9- and 25-dimensional Heisenberg-type nilmanifolds are (local) minima for the height. These nilmanifolds are related to the minima of the height of flat tori in dimensions one less. Finally, the left invariant metrics at which the height attains a global minimum on any three-dimensional nilmanifold are characterised by relating them to the height of flat 2-dimensional tori.

Das Hauptresultat dieser Arbeit ist ein regularisierter arithmetischer Satz von Riemann-Roch für ein hermitesches Geradenbündel, die isometrisch zum Geradenbündel den Spitzenformen vom geraden Gewicht ist, auf eine arithmetische Fläche, deren komplexe Faser isometrisch zu einer hyperbolischen Riemannschen Fläche ohne elliptische Punkte ist. Der Beweis des Resultats erfolgt durch metrische Degeneration: Wir regularisieren die betreffenden Metriken in einer Umgebung der Singularitäten, wenden dann den arithmetischen Riemann-Roch-Satz von Gillet und Soulé an und lassen schließlich den Parameter gegen Null gehen. Durch die metrische Degeneration entsteht auf beiden Seiten der Formel ein divergenter Term. Die asymptotische Entwicklung der Divergenz berechnet sich auf der einen Seite direkt aus der Definition der glatten arithmetischen Selbstschnittzahlen. Der divergente Term auf der anderen Seite ist die zeta-regularisierte Determinante des zu den regularisierten Metriken assoziierten Laplace-Operators, der auf den 1-Formen mit Werten in dem betrachteten hermitischen Geradenbündel operiert. Wir definieren und berechnen zuerst eine Regularisiereung des entsprechenden zu den singulären Metriken assoziierten Laplace-Operators; diese wird später im regularisierten Riemann-Roch-Satz auftauchen. Zu diesem Zweck passen wir Ideen von Jorgenson-Lundelius, D'Hoker-Phong und Sarnak auf die vorliegende Situation an und verallgemeinern diese. Schließlich beweisen wir eine Formel für den zum betrachteten hermitischen Geradenbündel assoziierten Wärmeleitungskern auf der Diagonalen bei einer Modellspitze. Diese Darstellung steht im Zusammenhang mit einer Entwicklung nach zur Whittaker-Gleichung assoziierten Eigenfunktionen, die im Anhang bewiesen wird. Weitere Abschätzungen des zum betrachteten hermitischen Geradenbündel gehörigen Wärmeleitungskern auf der komplexe Faser der arithmetischen Fläche schließen den Beweis des Hauptresultats ab. / The main result of the dissertation is an arithmetic Riemann-Roch theorem for the hermitian line bundle of cusp form of given even integer weights on an arithmetic surface whose complex fiber is isometric to an hyperbolic Riemann surface without elliptic points. The proof proceeds by metric degeneration: We regularize the metric under consideration in a neighborhood of the singularities, then we apply the arithmetic Riemann-Roch theorem of Gillet and Soulé, and finally we let the parameter go to zero. Both sides of the formula blow up through metric degeneration. On one side the exact asymptotic expansion is computed from the definition of the smooth arithmetic intersection numbers. The divergent term on the other side is the zeta-regularized determinant of the Laplacian acting on 1-forms with values in the chosen hermitian line bundle associated to the regularized metrics. We first define and compute a regularization of the determinant of the corresponding Laplacian associated to the singular metrics, which will later occur int he regularized arithmetic Riemann-Roch theorem. To do so we adapt and generalize ideas od Jorgenson-Lundelius, D'Hoker-Phong, and Sarnak. Then, we prove a formula for the on-diagonal heat kernel associated to the chosen hermitian line bundle on a model cusp, from which its behavior close to a cusp is transparent. This expression is related to an expansion in terms of eigenfunctions associated to the Whittaker equation, which we prove in an appendix. Further estimates on the heat kernel associated to the chosen hermitian line bundle on the complex fiber of the arithmetic surface prove the main theorem.

L’objectif de cette thèse doctorale est de contribuer à l’ensemble de la recherche sur les agences de notation. Elle couvre les trois aspects : théorique, conceptuel et empirique. La première partie se focalise sur le Néo-Institutionnalisme. Le Capitalisme d’État propre au marché chinois a été mis en avant, et un bilan comparatif a été dressé entre les marchés chinois et européens. Une analyse dynamique nous permet ensuite d’illustrer l’interaction des agences de notation avec les autorités régulatrices, les émetteurs de titres financiers, et les investisseurs. Dans la seconde partie, nous avons réalisé une vaste revue de la littérature, et proposé d’ajouter les spécificités institutionnelles chinoises aux variables déjà prises en compte dans les études. Au niveau de la méthodologie, certains outils qualitatifs et quantitatifs ont été envisagés. Diverses approches sont choisies en fonction du contenu de chacun des chapitres : le rôle, la stratégie et l’impact des agences de notation en Chine.Premièrement, par une approche comparative, nous avons montré qu'en Chine, le rôle des agences de notation ne se limitait pas à celui qui leur est habituellement assigné. Il semble aussi que les agences de notations se laissent tenter par le « rating shopping », le « split rating » et le « rating inflation », sous la pression des émetteurs. En revanche, les investisseurs sont relativement prudents lors de « multiples ratings ». Deuxièmement, nous avons mis en évidence que les agences de notation internationales ont tendance à noter plus strictement que les agences locales. Nous nous sommes rendu compte que les comportements stratégiques variaient d’une à l’autre, lorsque l’on étudie les déterminants des notations initiales des émetteurs. Troisièmement, en menant une étude d’événements sur le marché chinois des actions, nous avons trouvé des rendements anormaux significatifs sur quelques sous-échantillons des « modifications de notation », après avoir adopté différentes méthodes d’estimation, et mené divers tests paramétriques et non-paramétriques. Enfin, les analyses et résultats que nous avons apportés au cours de chaque chapitre empirique, ont enrichi en retour, nos discussions sur l’environnement institutionnel du marché chinois / In this Ph.D. thesis, we aim to contribute to the entire research on CRAs, with theoretical, conceptual and empirical aspects. We used the New-institutionalism as a theoretical frame of reference to justify the importance to have a good understanding of Chinese institutional characteristics. Chinese State-capitalism and Socialist-market economics, along with the interaction of CRAs with regulators, issuers and investors are devoted to setting the stage. We implemented various methodological approaches that seemed the most appropriate, on the sample that the most suitable, according to each of the objectives that we set, to better comprehend CRAs’ role, strategy and impact, under Chinese market context.Firstly, we found that CRAs were not expected to play “their main role” in assessing the credit default risk for market investment in China, as they are usually assigned to do so in Europe, and other developed countries. After running the frequency test, to register the words most used in the written regulatory and normative documents, we concluded that the expectation of roles of CRAs was also different in Continental China and in Hong Kong. At the expectation of issuers, CRAs also seem to play a role in rating “shopping”, in split rating, and even in rating inflation. Investors are very cautious to the multiple ratings. Secondly, by using logistic models, we found that global CRAs tend to rate more strictly than local CRAs, ceteris paribus. We also realized that the strategical behaviors of Chinese local CRAs are distinctive one from the other, when we studied the determinants “behind” initial issuer ratings. These findings confirmed the preliminary quantitative tests that we executed on the descriptive data. Thirdly, we failed to find informative impact of credit rating changes on the stock market, through a classic event study relying on the market model. Even if we refined the methodology by completing GARCH to OLS estimation model, and non-parametric tests to parametric tests, we only found significant outcomes in some subsamples, and for negative watch-lists.In the end, the analyses we led and the findings we reported from each of these empirical chapters have contributed to enrich, in return, our discussion of Chinese institutional characteristics

Submitted by Silvana Teresinha Dornelles Studzinski (sstudzinski) on 2016-08-25T13:11:13Z No. of bitstreams: 1 Luiz Felipe Jostmeier Vallandro_.pdf: 1279034 bytes, checksum: 2e83e11ab40a6df49542fe7525f4485f (MD5) / Made available in DSpace on 2016-08-25T13:11:13Z (GMT). No. of bitstreams: 1 Luiz Felipe Jostmeier Vallandro_.pdf: 1279034 bytes, checksum: 2e83e11ab40a6df49542fe7525f4485f (MD5) Previous issue date: 2016-06-14 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Este estudo investigou os fatores determinantes da direção da estratégia de diversificação de grupos empresariais no Brasil. Utilizando a teoria dos custos de transação (WILLIAMSON, 1975; 1979; 1985) e a teoria da agência (JENSEN e MECKLING, 1976) como pilares teóricos, o estudo se propôs a analisar a influência de um conjunto de fatores sobre a escolha da direção da estratégia de diversificação de grupos empresariais brasileiros, que ocorre no sentido de negócios relacionados ou não relacionados (diversificação relacionada X diversificação não-relacionada) à atividade principal do grupo. A estratégia empírica considerou uma amostra de 51 grupos empresariais identificados entre os 200 maiores grupos do Brasil entre 2009 e 2014, de acordo com a publicação do anuário Valor Grandes Grupos. A direção da diversificação tomou a forma de uma variável binária, com valor igual a 1 para a diversificação não-relacionada e zero para a diversificação relacionada. As variáveis utilizadas como os determinantes da direção da diversificação foram: lucratividade, endividamento, capex, risco, ativos físicos, ativos intangíveis, estrutura de propriedade considerando apenas um acionista controlador com ao menos 50% +1 das ações com direito a voto (Definido1), estrutura de propriedade formada por um grupo de acionistas compartilhando o controle (Definido2) e controle familiar. Duas variáveis de controle foram adicionadas: tamanho e oportunidades de crescimento. Os testes empíricos foram executados utilizando regressões probit painel para dados empilhados. As evidências sugerem que existe um conjunto de fatores que influencia a direção da estratégia de diversificação perseguida por grupos empresariais brasileiros. A principal conclusão é que fatores como endividamento, risco, capex e controle acionário exercido por um grupo de acionistas compartilhando o controle do grupo empresarial influenciam positivamente a probabilidade da escolha da diversificação não-relacionada. Por outro lado, fatores como ativos intangíveis e estrutura de propriedade considerando apenas um acionista controlador com ao menos 50% +1 das ações com direito a voto do grupo influenciam negativamente a probabilidade da escolha da diversificação não-relacionada. / This study investigated the determinants of the direction of diversification strategy of business groups in Brazil. Using both transaction costs theory (WILLIAMSON, 1975; 1979; 1985) and agency theory (JENSEN & MECKLING, 1976) as theoretical pillars, this study aimed to analyze the influence of a set of factors on the choice of the direction of diversification strategy of Brazilian business groups, that occurs towards related or unrelated businesses (related vs. unrelated diversification, respectively) to the main activity of the group. The empirical strategy considered a sample of 51 business groups identified among the 200 largest business groups in Brazil between 2009 and 2014, according to the publication of the yearbook Valor Grandes Grupos. The direction of diversification took the form of a binary variable, with the value of one for unrelated diversification, and zero for related diversification. The variables used as the determinants of the direction of diversification were: profitability, debt, capex, risk, physical assets, intangible assets, ownership structure considering only one shareholder holding at least 50% +1 of the shares with voting rights (Definido1), ownership structure formed by a group of shareholders sharing the control (Definido2), and family control. Two control variables were set: size and growth opportunities. Pooled probit panel regressions were used to run the empirical tests. The evidence suggest that a set of factors influences the direction of diversification strategy pursued by Brazilian business groups. The main conclusion is that factors like debt, risk, capex, and ownership structure formed by a group of shareholders sharing the control of the business group influence positively the probability of the choice of unrelated diversification. On the other hand, factors like intangible assets and ownership structure considering only one shareholder holding at least 50% +1 of the shares with voting rights influence negatively the probability of the choice of unrelated diversification.

This thesis addresses primary concepts in the humanitarian intervention debates. I argue that humanitarian intervention is a perfect duty. The global community has a moral obligation to act decisively in the face of extreme human rights abuses. There are two contrasting theoretical perspectives regarding international relations and humanitarian intervention: statism and cosmopolitanism. These contrasting perspectives contest the relative value of state sovereignty and human rights. Some of the most prominent ethicists in the debate have determined states have a “right” to intervene militarily in the internal affairs of other states to halt severe human rights abuses but there is no “duty”to intervene. These conclusions are largely based upon consequentialist considerations. This thesis argues a deontological perspective is essential. References to events Rwanda, Darfur, and Kosovo are made. There is a critical role for preemptive actions to play in addressing humanitarian crises and calls for global justice.

L'objectif de cette thèse est l'élaboration de modèles de contours actifs basés régions pour la segmentation d'images et de vidéos.<br />Nous proposons de segmenter les régions ou objets en minimisant une fonctionnelle composée d'intégrales de régions et d'intégrales de contours. Dans ce cadre de travail, les fonctions caractérisant les régions ou les contours sont appelées "descripteurs''. La recherche du minimum se fait via la propagation d'un contour actif dit basé régions. L'équation d'évolution associée est calculée en utilisant les outils de dérivation de domaines. Par ailleurs, nous prenons en compte le cas des descripteurs dépendant de la région qui évoluent au cours de la propagation du contour. Nous montrons que cette dépendance induit des termes supplémentaires dans l'équation d'évolution.<br /><br />Le cadre de travail développé est ensuite mis en oeuvre pour des applications variées de segmentation. Tout d'abord, des descripteurs statistiques basés sur le déterminant de la matrice de covariance sont étudiés pour la segmentation du visage. L'estimation des paramètres statistiques se fait conjointement à la segmentation. Nous proposons ensuite des descripteurs statistiques utilisant une distance à un histogramme de référence. Enfin, la détection des objets en mouvement dans les séquences à caméra fixe et mobile est opérée via l'utilisation hierarchique de descripteurs basés mouvement et de descripteurs spatiaux.

In this thesis, we present efficient deterministic algorithms for polynomial matrix computation problems, including the computation of order basis, minimal kernel basis, matrix inverse, column basis, unimodular completion, determinant, Hermite normal form, rank and rank profile for matrices of univariate polynomials over a field. The algorithm for kernel basis computation also immediately provides an efficient deterministic algorithm for solving linear systems. The algorithm for column basis also gives efficient deterministic algorithms for computing matrix GCDs, column reduced forms, and Popov normal forms for matrices of any dimension and any rank. We reduce all these problems to polynomial matrix multiplications. The computational costs of our algorithms are then similar to the costs of multiplying matrices, whose dimensions match the input matrix dimensions in the original problems, and whose degrees equal the average column degrees of the original input matrices in most cases. The use of the average column degrees instead of the commonly used matrix degrees, or equivalently the maximum column degrees, makes our computational costs more precise and tighter. In addition, the shifted minimal bases computed by our algorithms are more general than the standard minimal bases.

Background South Africa has experienced the most severe consequences of the HIV/AIDS pandemic. Every community has been affected in some way, many experiencing huge increases in mortality,particularly before antiretroviral therapies (ART) were readily available. However, the micro-level understanding of the HIV epidemic in South Africa is weak, because of a lack of detailed data for most of the population. This thesis is based on detailed individual follow-up in the Agincourt Health and Demographic Surveillance Site (HDSS) located in the Agincourt subdistrict of Mpumalanga Province and investigates micro-level determinants of HIV epidemiology and the impact of treatment provided. Methods The Agincourt HDSS has followed a geographically defined population since 1992,approximately the time when the HIV/AIDS epidemic first became apparent. This population based surveillance has included capturing details of all deaths, with cause of death determined by verbal autopsy, as well as the geographical location of individual households within the overall Agincourt area. Background information on the roll-out of ART over time was also recorded. Results A comparison immediately before and after the major roll-out of ART showed a substantial decrease in HIV-related mortality, greater in some local communities within the area than others. Individual determinants associated with a decreased risk of HIV/AIDS mortality included proximity to ART services, as well as being female, younger, and in higher socioeconomic and educational strata. There was a decrease in the use of traditional healthcare sources and an increase in the use of biomedical healthcare amongst those dying of HIV/AIDS between periods before and after the roll-out of ART. Conclusions Understanding micro-level determinants of HIV/AIDS infection and mortality was very important in terms of characterising the overall epidemic in this community. This approach will enable public health interventions to be more effectively targeted towards those who need them most in the continuing evolution of the HIV/AIDS epidemic.

Bakalauro baigiamajame darbe nagrinėjama savitarna lyginant ją su tradicine paslauga prekybos centruose Lietuvoje bei naujos paslaugos įtaka jos vartotojams. Teorinėje dalyje pateikta savitarnos esmė ir bendrosios jos savybės, savitarnos valdymo veiksnių analizė (naudojimosi savitarna lemiami veiksniai, savitarnos priėmino veiksniai), aptarti savitarnos technologijos tinkamumo kriterijai bei savitarnos reikšmė aptarnaujant klientus. Darbo problema. Stiprėjanti konkurencija paslaugų sektoriuje skatina paslaugų įmones ieškoti naujų verslo technologinių sprendimų, kurti naujas paslaugų technologijas, kurias taikant paslaugos teikiamos efektyviau. Savitarnos technologijos taikymas aptarnaujant vartotojus yra efektyvesnis negu individualizuotas, tačiau nevisos savitarnos paslaugos prigyja. Savitarnos pripažinimas iš vartotojų pusės yra susijęs su pasitikėjimu paslaugos teikėju, todėl yra svarbu nustatyti veiksnius darančius įtaką vartotojų suvokimui apie pačią paslaugą ir nustatyti savitarnos mašinų reikalingumą Lietuvos prekybos centruose. / This bachelor final paper analyses self-service comparison to traditional service of shopping centers in Lithuania and the input of self-service technology on service users. Theoretic chapter provides the analysis of the essence and general properties of self-service as well as analysis of the self-service operate factors (the use of self-service determinant factors and self-service adoption factors), discussion of the eligibility criteria for self-service technology and self-service importance for customer needs. Work problem. Increasing competition in the services sector encourages service companies of finding new technological solutions for their business and create new technology based services for more efficiency. Self-service technology for customer servicing is more effective than individualized but not all self-service naturalize. Self-service recognition from the consumer side is related to the trust of the service provider, so it is important to identify the factors influencing consumer’s perceptions of service and the need for self-checkout alternative in shopping centers of Lithuania.